Cross-coupling alkynyl-alkenyl

With the aid of a fluoride ion source, alkynyltrimethylsilanes work as effective alkynyl donors in the Pd-catalyzed cross-coupling with alkenyl iodides.43,43a Recent studies have revealed that the alkynylsilanes react smoothly with aryl iodides and triflates, alkenyl triflates, or alkynyl chlorides under co-catalysis by a Cu or Ag salt.45 46a The use of a Pd/imidazolium chloride system in the presence of Cs2CC>3 and a Cu co-catalyst enables an efficient coupling between alkynyltrimethylsilanes and aryl bromides.47 In some cases, this catalytic system works well under Cu-free conditions. Alkynylsilanols also can be used as alkynyl donors in the coupling with aryl iodides.48 49 When TBAF is employed as activator, the coupling proceeds efficiently without co-catalyst.48... 

The three principal palladium-mediated reactions of interest in the synthesis of vitamin h(l) and carotenoids are (a) allylic alkylation of 7C-allylpalladium complexes, (b) Heck-type couplings, and (c) cross-coupling of alkenyl and alkynyl metal derivatives. 

Last year s reports that 1-alkenylboranes cross-couple with alkenyl, alkynyl, or aryl halides in the presence of palladium catalysts have now been extended to allylic bromides, providing a new synthesis of 1,4-dienes (e.g. Scheme 89). ... 

Carbonylative cross-coupling of various iodonium salts bearing transferable aryl, heteroaryl, alkenyl, alkynyl residues with phenylboronic acid takes place under mild conditions giving the respective ketones in high yields (Equation (16)). The yields of competing cross-coupling do not exceed 8%. 

Various aryl, alkenyl and even alkylborane reagents of different reactivity can be used for coupling with aryl, alkenyl, alkynyl and some alkyl halides, offering very useful synthetic methods. The cross-coupling of aryl and heteroarylboronic acids with aryl and heterocyclic halides and triflates provide useful synthetic routes to various aromatic and heteroaromatic derivatives. Sometimes, the reaction proceeds in the... 

The Suzuki Coupling, which is the palladium-catalysed cross coupling between organoboronic acid and halides. Recent catalyst and methods developments have broadened the possible applications enormously, so that the scope of the reaction partners is not restricted to aryls, but includes alkyls, alkenyls and alkynyls. Potassium trifluoroborates and organoboranes or boronate esters may be used in place of boronic acids. Some pseudohalides (for example triflates) may also be used as coupling partners. 

Alkynyl(trimethyl)silanes smoothly couple with alkenyl halides at room temperature in the presence of a palladium catalyst and TASF (Eq. 5) [4]. The difference in reactivity between alkynylstannanes and -silanes were utilized in a palladium-catalyzed three component cross-coupling reaction. Thus, the palladium-catalyzed sequential reaction of tributylstannyl(trimethylsilyl)ethyne... 

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